Numerous commercially valuable plants, including common agricultural crops, are susceptible to attack by fungal pathogens. In turn, many plants produce proteins with antifungal activity, such as thionins, beta-1,3-glucanases, chitinases, and plant defensins. Plant defensins are small cysteine-rich proteins of 45-54 residues and four intramolecular cysteine bonds (see, Terras et al., 1995, Plant Cell 7:573-88). Transgenic plants over-expressing natural defensins have enhanced resistance to fungal diseases (Gao et al., 2000, Nat. Biotechnol. 18:1307-10; Terras et al., 1995, Plant Cell 7:573-88; De Bolle et al., 1996, Plant Mol. Biol. 31:993-1008). However, the resistance is not robust enough to render the plants commercially valuable. There is a need for new antifungal compounds and new methods of inhibiting fungal infection of plants and other organisms.